This is a hard one and I can see why you decided to post it here. B is most definitely wrong but the other three are all neck and neck. There are both even pros and cons of A and C but I think it would be more reasonable to adopt a general routine. So I think the answer would be C.
Predicate nominative is also popularly known as the predicate noun. It is a noun, a pronoun or any nominal that follows the linking verb and most of the time the form of the verb be. It links or completes the linking and change the name of the subject. It complements or completes the verb in the sentence. However, predicate nominative completes only linking verbs. Predicate nominative can be compound while some do not have one. Therefore in the sentence "Sugar is the main ingredient in taffy", the predicate nominative is "ingredient".
Medical Dictionary, Hope this helps ^^
They act logically rather than emotionally, are able to consider how a decision or event impacts people outside of themselves, and take time to make big decisions.